Safety fencing sword

ABSTRACT

A fencing sword, especially an epee or a foil, whose blade is provided with at least one groove defining a strain concentration zone, dimensioned to rupture longitudinally to separate two longitudinal parts of the blade from one another so that, with subsequent impacts, there is a change in the nature of the sound generated by impact. The rupture occurs when the metal fatigue reaches a point at which transverse rupture might be expected so that the sound change can inform the user of the need to discard the blade.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national phase application corresponding toPCT/FR86/00160 filed May, 7, 1986 and based, in turn, on French nationalapplication No. 85.07459 filed May, 10, 1985 under the InternationalConventional.

FIELD OF THE INVENTION

My present invention relates to a safety fencing sword, and moreparticularly, to a fencing sword capable of signalling to the fencer ofmetal fatigue condition resulting from use of the sword which can beassociated with a transverse rupture of the blade.

BACKGROUND OF THE INVENTION

Traditionally fencing swords, namely foils, epees and sabers are made oftreated, alloyed or carbon steel.

Under repeated impact, through mutual contact between the two blades,but also due to the intense strains to which the blades may besubjected, the metal the blades are made from becomes hard and brittleand eventually breaks. When a transverse rupture occurs during anattack, the blade portion still in the hand of the fencer, with its endsectioned off and generally bevel-edged, becomes a dreadful weapon,capable of penetrating the protective garment and the body of thecomponent, with the risk of killing him. To remedy this, it has beenconsidered to make the blade of an age-hardening steel, incorporatingnickel and titanium, with or without the addition of molybdenum andcobalt. Experience shows these blades to be more durable, but undercertain conditions of severe use, the blade may still break transverselyjust like blades of the common alloyed steels. It seems therefore thatthe age-hardening steels delay the problem, but do not completely solveit.

OBJECT OF THE INVENTION

It is the object of the present invention to remedy this inconvenience,by creating a safety sword able signal the moment when the blade may beaffected by a risk of breakage and has to be discarded.

SUMMARY OF THE INVENTION

For this purpose, the blade according to the invention comprises atleast on a portion of its length extending from its free end, alongitudinal area of reduced cross section, concentrating therein thestrains to which of the blade subjected and which, when the material theblade is starts to manifest a fatigue which is liable to result in itstransverse rupture, is capable of longitudinally dividing intolongitudinal fragments, thus indicating the state of fatigue of themetal.

Thus, when the metal constituting the blade reaches a state of fatiguecapable of inducing transverse breakage, the strains to which the bladeis subjected during a match bring about the break of the strainconcentration zone, at least on one portion of the length of the blade.The longitudinal crack created thereby changes the physicalcharacteristics of the blade, which results in a different sound atimpact. These modifications in the physical and acoustic characteristicsalert the two fighters that they a rupture interrupt their match inorder to replace the defective sword, thus preventing any body injury.

The particular construction of the blade of the invention allows for thesubstitution of a longitudinal split in the blade for the extremelydangerous transverse rupture, without danger to the fencers.

In the case of a foil, the longitudinal breaking zone comprises an axialweb which is defined by two deep, longitudinal grooves, opening from thesmall faces of the blade, conferring to this zone an "H"-shaped section,and the thickness of the web, in cross section, increases proportionallywith the increase in the blade cross section, from the extremity of theblade to the end of the breaking zone.

With this design, the sword is lighter and all the strains thereonduring a match, are distributed over the web and over its length. Inaddition, the cracks occurring in the wings of the H-cross section ofthe blade, as a consequence of metallographic structural transformationsin the metal during attacks and impact-related, are confined to thestrain concentration zone and cause a transverse rupture of the bladeonly over half of its thickness.

For an epee having an approximately "V"-shaped cross section, thelongitudinal breaking zone is arranged on the back rib, between theexterior face of this rib and the bottom of a longitudinal grooveopening into the concavity of the "V"-section, and increasing in crosssection proportionally with the increase in the cross section of theblade, from its extremity to the end of the breaking zone.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be better understood with the aid of the followingdescription, reference being made to the accompanying schematic drawing,representing examples of embodiments of a foil and of an epee, accordingto the invention. In the drawing:

FIG. 1 is a perspective view of a foil;

FIG. 2 is a view in longitudinal section taken along the line II--II ofFIG. 1;

FIGS. 3, 4 and 5 are sectional views along the line III--III, IV--IV,V--V of FIG. 2, representing, on a larger scale, partial sections of theblade.

FIG. 6 is a view in transverse section similar to FIG. 4 of anotherembodiment;

FIG. 7 is a perspective view of the blade of an epee;

FIG. 8 is a longitudinal section along the line VIII--VIII of FIG. 7;

FIG. 9 is an elevational view into the hollow of the blade of FIG. 7;

FIGS. 10, 11, 12 and 13 are transverse sectional views along lines X--X,XI--XI, XII--XII, XIII--XIII of FIG. 8, showing transversal sections ofthis blade on a larger scale; and

FIGS. 14 and 15 are fragmentary side elevational views on a largerscale, of the blade of a foil in two embodiments of the breaking zone.

SPECIFIC DESCRIPTION

In FIGS. 1 to 6, a foil blade 2 has a tip extended with a threaded stud3 and a base extended with a threaded rod 4, for mounting a handle. Thisblade has a cross section of a generally rectangular shape.

According to the invention, this blade is formed with two longitudinal,deep grooves 6, starting from its two small faces and giving an H-shapedcross section, formed by two wings or flanges 2a connected by a web 2b.More precisely, the two parallel bottoms 6a of the grooves 6 definebetween them in the breaking area 7, a strain concentration zone,corresponding to the web 2b of the H-shaped cross section. Each of thebottoms 6a is joined with the corresponding lateral faces 6b, withcorner roundings or fillets 8. As shown in FIGS. 3 to 5, for the length"1" which controls the breakage starting from its extremity toapproximately half of its length, the grooves have a depth p₁ to p₂,which keeps increasing approximately proportional with the increase ofthe dimensions T1 to D1, T2 to D2 of the blade cross-section, so thatthe web 2b has in the zone 7 a thickness e1 to e2, increasing alsoproportionally with the increase of the cross section, in order toprovide a constant resistance over this length. Beyond this length, asshown in FIG. 3, the grooves have a constant depth P and the thickness Eof the web 2b keeps increasing until it reaches the base.

When this blade is used, the repeated shocks and alternate compressionand extension strains affecting the wings of the "H"-shape aretransmitted over the entire length of the web 2b. As a result, any metalfatigue affects first the zone 7, which due to its reduced thickness isthe first one to yield. The break does not occur transversally, as inthe case of traditional swords, but longitudinally on at least oneportion of the length of the blade and is characterized by alongitudinal crack separating the two wings of the H-shaped crosssection. This break affects the resistance of the elasticity of theblade and also changes the sound the blade makes on impact, thusproviding and indication for the need to replace the blade.

These grooves define therefore a longitudinal zone 7 which byconcentrating the strains not only anticipates the dangerous transversebreaking of the blade, but also changes the preferred direction ofrupture to a longitudinal one and informs the user that his blade has tobe discarded.

In the embodiment represented in FIG. 6, the grooves 6 are provided withlateral faces or flanks 6b, convergently angled towards the outside,resulting in a trapezoidal cross section whose small base is the opening6c the blade forming the mouth of the groove. The opening 6c has aheight h smaller than the diameter of the jacket 11a of the wire 11which is to be arranged in the groove 6 for transmitting the toucheswith electrical foil of the opponent's protective garment in matches.

As shown in the left side of FIG. 6, the mounting of the wire in itslocation in the corresponding groove 6 is performed by applying apressure on its sheath 11a towards the bottom of the groove, so that thesheath 11a is elastically deformed while passing through the opening 6c.When the conductor is located within the groove 6, its outer sheathresumes its initial dimensions, due to its own elasticity. As shown onthe right side of the same figure, the sheath 11a cooperates with theangled faces 6b of the groove, which insures that the conductor stayswithin the groove without glueing.

Because of this arrangement the conductor 11 is kept perfectly withinthe groove and can not exit therefrom, even when the blade is subjectedto considerable flexure. During such flexure, the conductor in itsinsulating coating can slide within the groove 6, without disturbing itsposition within the groove or the functioning of the wire.

Finally, this way of keeping the conductor in place within the grooveconsiderably facilitates its replacement, because it is no longernecessary to perform delicate operations, such as to unglue thedefective conductor with the aid of solvents and to glue a new conductorin the groove. The groove with a trapezoidal cross section can beprovided only on one side of the foil.

The epee 10 shown in FIGS. 7 to 13 has a "V"-shaped cross section,defining an outer rib 12, running from the tip 13 to the base 14. Thetip is provided with a threaded stud 15, while the heel is extended witha threaded rod 16.

According to the invention, this epee also has on a portion of itslength for instance on half of its length as represented by the sgement1, starting from the extremity of the epee, a longitudinal zone 17 forstrain concentration and for longitudinal breaking. This zone isarranged in the back rib between the outer face 12 constituting this riband the bottom 18a of a groove 18 originating from the concavity of"V"-shaped cross section of the epee. On the length portion 1 of theblade, the depth P1 to P2 of the groove 18 increases, as in FIGS. 12 and13, from the tip 13 of the blade and proportionally with the variationsof the dimensions T1 and D1 of the cross section of the blade. Thelongitudinal breaking zone 17 has a thickness e1 to e2, which keepsincreasing from the tip of the blade to the end of the longitudinalbreaking zone 7. From that point on and continuing towards the base 14,the depth of the groove 18 decreases, reaching a point where the bottom18a of the groove is flush with the bottom 20 of the blade profile asshown in FIG. 10. The area where this leveling occurs, is situated at adistance L from the extremity of the blade exceeding the distance 1.

With this arrangement, when the metal constituting the blade reaches thepoint of breaking due to fatigue, the break takes place in the area ofstrain concentration 17, in the form of a crack separating the two wingsof the "V"-shaped cross section. As in the case of foils, this breakageinduces a modification of the elastic characteristics of the blade andof the sounds it makes on impact, warning the user that the match mustbe stopped and the blade discarded.

The thickness of the longitudinal breaking zone 17 of the epee can alsobe controlled by machining the face 12 with or without machining of thegroove 18.

It has also to be noted that the thickness e1 to e2 of the strainconcentration zone 17 of the epee, as well as the thickness e1 to e2 ofthe strain concentration zone 7 of the foil 2, is smaller than thethickness z of either one of the wings 10a-2a connected by them, in amanner as to ensure the formation of a breaking zone.

The groove 6-18, which makes possible the mastering of all geometriccharacteristics of the strain concentration zone, can be formed in anyof the materials the blades can be made from. But its manufacture issimpler, less expensive and faster in the case of blades made ofage-hardening alloys, while such blades are in a tempering stage wherethe material has a high plasticity and a low hardness; after theformation of the grooves 6 and the rest of the machining is concluded,the blade is hardened by raising the temperature.

In embodiments shown in FIGS. 14 and 15, the web of the foil 2 iscrossed, in the area of its longitudinal breaking zone 7, by openings.These openings of circular shape as shown at 21 in FIG. 14, or of oblongshape, as shown at 22 in FIG. 15, are distributed according to a regularor irregular pitch. They define bridges of material, respectively 23-24which increase the strain concentration and constitute ruptureindicators. The oblong openings 22 are inclined by 30°-60° with respectto the longitudinal axis of the foil, and are separated by a smallpitch, so that the anterior extremity of each opening is located beyondthe posterior extremity of the preceding opening or at least at the samelevel therewith. In an embodiment not shown here, they can also belocated in any manner on both sides of the longitudinal axis of theblade, holding parallel to this axis. The transverse size of eachopening is less than 1 mm and of the order of a few tenth of amillimeter. As shown also in FIGS. 12 and 13, such perforations 21 or 22can also be provided in the longitudinal rupture zone of the epee, withor without groove 18.

In the preceding embodiments it has been indicated that the longitudinalbreaking zone extends over one half of the length of the blade, but itis obvious that this size is given only as an example, and that it canalso range between one third and two thirds of the length, or even more.The length of breaking zone can vary depending on the characteristics ofthe material of the blade which can be steel, a forged alloy, but also acomposite material.

I claim:
 1. A safety fencing sword capable of providing an audibleindication of metal fatigue, comprising:an elongated blade having a tipat one end and means for mounting a handle at an opposite end of theblade; and at least one groove formed in said blade and subdividing sameover at least a portion of the length of said blade from said tip intoat least two elongated blade parts held together by a strainconcentration zone fixedly and unitarily interconnecting said parts foreffective fencing, said strain concentration zone being dimensioned andconfigured to rupture longitudinally upon the development of afencing-use-generated fatigue of the material approaching atransverse-breakage condition to cause exclusive longitudinal separationof said parts at said portion of said blade, thereby altering a soundgenerated by the blade upon impact.
 2. The safety fencing sword definedin claim 1 wherein said blade is the blade of a foil which is formedwith said portion with two longitudinally extending grooves extendinginto said blade from opposite sides and defining between them a webconstituting said strain concentration zone, said grooves forming saidblade into an H cross section, said web increasing in thicknessproportionately to an increase in said cross section over the length ofsaid portion from said tip.
 3. The safety fencing sword defined in claim2 wherein at least one of said grooves has a narrow portion at a mouththereof and is defined by a pair of flanks converging toward said mouth,an electrical conductor being lodged in said one of said grooves andbeing held in place by said narrow portion.
 4. The safety fencing sworddefined in claim 2 wherein said grooves have mutually parallel bottomsadjoining flanges defined by said grooves in said portion of said bladeby respective rounded fillets.
 5. The safety fencing sword defined inclaim 1 wherein said blade is the blade of an epee having a generallyV-shaped cross section and provided with a rib substantially at thevertex of the V, said rib forming said strain concentration zone with arounded bottom of said groove, said strain concentration zone increasingin thickness proportionately with an increase in thickness of the crosssection of said blade to said tip.
 6. The safety fencing sword definedin claim 1 wherein said zone has a thickness at any cross section ofsaid blade along said portion which is less than the thickness of saidparts interconnected by said zone.
 7. The safety fencing sword definedin claim 1 wherein said zone is formed with throughgoing openings spacedapart along said portion.
 8. The safety fencing sword defined in claim 7wherein said openings are circular.
 9. The safety fencing sword definedin claim 7 wherein said openings are elongated.
 10. The safety fencingsword defined in claim 9 wherein said openings are inclined to alongitudinal dimension of said blade and overlap therealongtransversely.